Not sure how many people have tried to actually make international address forms, but it's really difficult. Despite a lot of searching, I have yet to find any

Not sure how many people have tried to actually make international address forms, but it's really difficult. Despite a lot of searching, I have yet to find any web site or book or library that can handle all international addresses properly while still letting you validate that the data is reasonable (city/state/postal code) etc. It's not that American-run web sites don't want to support international formats, but when 95% of your business is from America, it just doesn't make business sense to deal with the complexity of international addresses for 5% of your revenues. I'd love it if someone can point me to a library/book/tutorial of the appropriate way to handle this situation. NOTE: I haven't looked that recently, but did about a year ago.